Fuel pump



E. A. JOHNSON March 10, 1959 FUEL PUMP Filed Dec. 19, 1955' 2 Sheets-Sheet 1 FIG.3.

, INVENTOR.

ELDON A. JOHNSON aw mu ATTORNEY March 1959 E. A. JOHNSON 75,

FUEL PUMP Filed Dec. 19, 1955 2 Sheets-Sheet 2 INVENTOR. ELDON A. JOHNSON AIIO R NE Y United States Patent FUEL PUMP Eldon A. Johnson, St. Louis, Mo., assignor, by mesne assignments, to ACE Industries, Incorporated, New York, N. Y., a corporation of New Jersey Application December 19, 1955, Serial No. 554,090

1 Claim. (Cl. 103-150) This invention relates to a diaphragm type of fuel pump for automotive use and, more specifically, to a pump construction which is more compact, permitting a substantial increase in capacity for the same size of pump, or a substantial reduction in the outside dimensions of the pump without a reduction in pump capacity.

Because space is at a premium within the zone in which the fuel pump must be located on an engine, compactness in design is always desirable. There are cases Where the space limitation is so critical that a reduction in pump dimensions amounting to a fraction of an inch, when obtained without the loss of pumping capacity, is a decided competitive advantage.

This invention discloses one way in which pump dimensions can be reduced, and this advantage gained.

According to this invention, the fuel pump is constructed so that the bosses containing the holes for the fastening screws securing the pump body assembled project from the diaphragm clamping flanges into the pumping chamber rather than outwardly therefrom, as has been the usual practice. Because of this change, the casing flanges clamping the diaphragm can be made continuous and circular and located radially outwardly of the ring of screw holes. Portions of the pumping chamber extend radially between the bosses so that the active pumping area of the diaphragm and the capacity of the pump is increased. At the same time, there is a net reduction in pump size over conventional pumps of comparable capacity. When compared with the standard type of pump of the same size, a net gain in capacity can be shown of 16 or 17 percent.

One form of the instant invention is illustrated in the accompanying drawings, in which:

Fig. 1 is an elevation, partly in section, of a pump constructed according to the teachings of this invention.

Fig. 2 is a bottom plan view of the valve casing of the pump shown in Fig. 1.

Fig. 3 is a fragmentary elevation, partly in section, illustrating the action of the diaphragm at the opposite end of the pumping stroke from that in Fig. 1.

Fig. 4 is a plan view of the diaphragm on the valve casing.

Fig. 5 is a similar view showing the deformation of the diaphragm during the looping operation.

Fig. 6 is a side view of Fig. 5 with parts in section along the line 6-6 of Fig. 5.

Fig. 7 is a top plan with parts broken away to show the diaphragm in the assembled pump.

Referring to the drawings, the fuel pump illustrated, generally indicated as P, has a pumplbody composed of several sections such as a rocker arm casing 1, a valve casing 2, and a cap 3, secured together in assembled relation in any suitable manner. A rocker arm 4 pivoted on the pin 5 in the housing 1 is adapted to engage and be driven by an eccentric on the camshaft of the engine. A flange 6 is provided with suitable bolt holes for securing the rocker housing to the engine. The rocker arm 4 is held against the eccentric by a spring 7.

Within the rocker arm casing 1 is a stem 9 operated in one direction on the intake stroke of the pump by the rocker arm 4, and in the other direction by the pump spring 10. The upper end of the stem 9 has a shoulder 11 supporting the backing plates 12 and 13, which clamp the diaphragm 14 in position on the stem 11.

Backing plates 12 and 13 are formed with inner and outer peripheral flanges 15 and 16, which turn in the same direction. Due to the clamping pressure exerted between the backing plates, the diaphragm 14 is compressed centrally, resulting in a preformed loop in the diaphragm. The distortion due to the compression between the backing plates causes the loop in the diaphragm to form and to extend into the pumping chamber, and prevents reversal, all as disclosed in my prior co-pending application with Jack M. White, Serial No. 456,360,. filed September 16, 1954, now Patent No. 2,840,003.

Diaphragm 14 is clamped at its periphery between the flanges 19 and 20 on the pump housing 1 and valve casing 2, respectively. Screws 21 secure the flanges 19 and 20 in clamping engagement with the diaphragm 14.

As mentioned heretofore, considerable saving can be made in outside pump dimensions by locating the screw holes for securing the valve casing to the rocker housing within the periphery of the flanges 19 and 20, so that the bosses containing the screw holes extend within the.

pumping chamber. Figs. 2 and 3 illustrate this feature.

Fig. 2 is a view of the pump chamber 24 with the diaphragm 14 removed.

Flange 20 is substantially of uniform width, giving an uninterrupted clamping surface for engaging one surface of the diaphragm 14 and sealing the pump against leakage. Projecting inwardly of the flange 20 are a series of bosses 26 which have their diaphragm abutting surfaces coplanar with the adjacent surface of the flange 20. The cooperating flange 19 on the rocker housing 1 is of sufficient Width for adequate sealing, and preferably is coextensive in width with the lower surface of the flange 20 and the bosses 26, so that elfective sealing is obtained around the holes 25, as well as at the outer flange 20.

The location of the bosses 26 within the pump chamber 24 forms a pump chamber with scalloped edges. Where the pump is provided with five bosses for five screws 21, the chamber 24 will have a corresponding number of recesses 32 forming a scalloped outline for the pump chamber 24.

Fig. 3 shows the position of the parts at the opposite end of the suction stroke. This view indicates quite readily the increase in displacement possible by comparison of the position of the parts on the left-hand side of Fig. 3 with that on the right.

At the opposite end of the stroke, shown in Fig. l, the diaphragm is tightened, within the recesses 32, as illustrated at the right, and rolls into engagement with the side of the bosses 26, as illustrated at the left-hand side of the pump. Due to the fact that the recesses 32 are on opposite sides of the bosses 26, the material in the diaphragm adjacent the bosses 26 can flow chordwise, due to its inherent resilience, and reduce the friction caused by the compression of the diaphragm between the side of the bosses 26 and the opposite edge of the backing plates 15 and 16. This permits a closer operating clearance between the plates and the casing than would be otherwise possible if the pump chamber 24 were co-extensive with the inside of the bosses 26.

Operation Rocking movement imparted by the eccentric to the cam 4 will produce reciprocation of the stem 6 between Patented Mar. 10, 1959 the extreme positions shown in Figs. 1 and 3. During movement of the stem on' the discharge stroke, the diaphragm 14 will be drawn tight against the shallow recesses'32'by tension. On the other hand, the diaphragm 14 rolls into engagement with the inside of the bosses 26, thus increasing the displacement of the pump by reducing the clearance between the inner surface of the pump chamber 24 and the diaphragm 14. On the suction stroke, the reverse action happens, withdrawing the diaphragm 14 completely from the shallow recesses 32 and from engagement with the inner surface of the bosses 26. The location of the screw hole bosses within the pump chamber therefore not only decreases the operating clearance between the parts, but also permits a decrease in the outside dimensions of the pump by reducing flange width,

Assembly Figs. 4 to 7, inclusive, are not only included here to illustrate the manner of assembly, but also for the purpose of facilitating a better understanding of the manner of the cooperation between the diaphragm and the pump chamber. In Fig. -4 the diaphragm is shown superimposed upon the flange 20 of the valve casing 2. Particular attention is directed to the fact that the diaphragm is slightly larger than the casing flange 20. This design is intentional, and provides the added material in the diaphragm necessary to permit the full discharge stroke illustrated in Fig. 1. Since pump capacity is a direct function of diaphragm size, it will be appreciated that this view has added significance.

In Fig.- 5, the backing plates 12 have been forced into the pump chamber 24 preparatory to the final assembly of the pump. Diaphragm 14 assumes a position as dis closed with the edges thereof raised in "a peculiar scalloped pattern. This is further illustrated with reference to Fig. 6, showing a side view with the pump parts positioned as in Fig. 5.

In Fig. 7, rocker housing 1 is shown assembled with the valve casing. The assembly operation compresses the edge of the diaphragm 14 to a fiat condition and secured between the pump parts by the screws 21. In Fig. 7, the dotted line indicates the portion of the diaphragm clamped.

A comparison of Fig. 4 and Fig. 7 illustrates two factors indicating the gain in pump capacity which may be realized by practicing this invention. are an increase in diaphragm area which is gained because of this design, and its effective use in the actual displacement of fuel. Each contributes to a material gain in capacity conservatively estimated as from 16 to 17 percent over pumps otthe same size in which the screw holes are located within the margins of the casing flanges.

Certain structures have been described herein which will fulfill all the objects of the present invention, but it is contemplated that other modifications will be obvihas to those skilled in the art which come within the scope of the invention as defined by the appended claim.

I claim:

A fuel pump comprising a pumping diaphragm, casing members having peripheral flanges for clamping the periphery of said diaphragm therebetween, one of said members forming a pumping chamber with said diaphragm, said one member having fluid inlet and outlet ports for said pumping chamber, and securing bosses on said one member spaced around said flanges, the portions of said pumping chamber between said bosses projecting radially outwardly therebetween to form a scalloped perimeter for said pumping chamber and thereby provide maximum pump chamber capacity in relation to the peripheries of said flanges.

No references cited.

These factors- 

